1. Field of the Invention
This invention relates to a method and an apparatus for sensing a magnetic field and for detecting a magnetic flux density, each as a function of a measured Lorentz force.
2. Discussion of Related Art
Hall sensors have been used to sense magnetic fields. Hall effect transducers have been used with pole pieces and biasing magnets to increase sensitivity of the Hall sensors. When used with a magnet, a pole piece tends to channel a magnetic field and thus change flux densities in a magnetic circuit.
U.S. Pat. No. 4,992,659 discloses a microscopy apparatus for measuring Lorentz force-induced deflection of a tip of a scanning tunneling microscope to image magnetic structures of a sample. Motion of the tip, which indicates the presence of a magnetic field, is optically detected. The magnetic field measurement and a tip position are received by a computer which provides an output signal to a device for graphically representing the magnetic field at different positions on a surface of the sample.
U.S. Pat. No. 5,675,252 discloses a piezomagnetometer which uses a magnetoelectric composite structure, formed by alternating layers of piezoelectric and magnetostrictive material, to convert a fluctuating magnetic field directly to electric current. An ambient magnetic field strains magnetostrictive layers which stresses piezoelectric layers and drives a polarization current proportional to an amplitude of the magnetic field.
It is apparent that there is a need for a method and apparatus that enables a microelectronic structure to sense a magnetic field and to measure a magnetic flux density. There is also a need for a method and apparatus that produces a significantly higher output voltage, as compared to conventional methods and apparatuses, when exposed to the same magnetic field.